The present disclosure relates to a solid-state imaging device, and an electronic apparatus such as a camera including the solid-state imaging device.
As a solid-state imaging device (an image sensor), a CMOS solid-state imaging device, a CCD solid-state imaging device and the like are suggested. The solid-state imaging device is used in a digital still camera, a digital video camera, various types of portable terminal equipment such as a mobile phone including a camera, or the like. In recent years, accompanying miniaturization and lowered power consumption, a CMOS solid-state imaging device has been often used. In addition, a backside-illumination type of the CMOS solid-state imaging device has been developed in which a thinned semiconductor substrate is used, a pixel region including photodiodes in one surface (a light sensing surface) side of the semiconductor substrate is formed, and a multilayer wiring layer including wirings in a plurality of layers is installed in the other surface side of the semiconductor substrate opposite to the pixel region.
In the backside-illumination type of the solid-state imaging device, since it is necessary to read and process a signal charge from the light sensing surface side of the semiconductor substrate to a signal processing circuit which is formed in the surface side opposite to the light sensing surface side, the thickness of the semiconductor substrate is thinned. Therefore, when light having a long wavelength such an infrared light is incident, the light may be easily transmitted to the multilayer wiring layer side, and the light, which is reflected at a supporting silicon substrate surface bonded to the multilayer wiring layer or at the wiring of the multilayer wiring layer, may be incident to photodiodes of the adjacent pixels and color-mixed. In addition, the incident light may be incident to an optical black region which determines a shielded optical black level disposed at the outside of an effective pixel region of a pixel region, and a darkening problem which recognizes the pixel region as black in the state where the light is incident to the effective pixel region may occur.
As methods for suppressing color-mixing, the related arts are suggested in Japanese Unexamined Patent Application Publication Nos. 2009-259934, 2005-217439, and 2009-158944. In Japanese Unexamined Patent Application Publication No. 2009-259934, by installing an infrared ray cut filter film or a light shield film between the photodiode and the wiring layer, the infrared light which is transmitted to the light sensing surface and reflected at the wiring layer is cut, and color-mixing is prevented.
In Japanese Unexamined Patent Application Publication No. 2005-217439, in a process for manufacturing the backside-illumination type of the CMOS solid-state imaging device, a silicide film which is used in a gate electrode of a MOS transistor or an active region also remains in the photodiode region (the side opposite to the light sensing region). Thereby, the light which is incident from the rear surface is transmitted to the photodiode and reflected at the wiring, and the separated photodiode is prevented from being subjected to a photoelectric conversion.
In a solid-state imaging device disclosed in Japanese Unexamined Patent Application Publication No. 2009-158944, a layer wiring is formed, and an inner-optical filter layer cutting an infrared ray is formed in the lower layer of a color filter at the upper layer of an inner-layer lens. Thereby, sensitivity is improved and occurrence of color-mixing is suppressed.
Japanese Unexamined Patent Application Publication No. 2008-91753 discloses a device which simultaneously and independently obtains a color image and an infrared image using a single image sensor.